This patent application is related to my copending patent application Ser. No. 949,938, filed Oct. 10, 1978 now U.S. Pat. No. 4,241,629.
This invention relates to methods and apparatus for cutting a continuous expanded lead battery grid structure and finds adaptation in the battery grid industry, and in particular, relates to the formation of individually pasted battery grid structures produced therefrom.
The subject invention specifically is addressed to the manufacture of individual storage battery grids having active material embedded within the grid network thereof. Such grid structures are generally made by expanding a metal sheet to form an open network structure and thereafter applying paste thereto by means readily available in the art.
Cutting and separating devices of the drum or roller type, and particularly web cutting machines, are known in the art and generally comprise two adjacent cylindrical rollers, one of the rollers having a knife blade protruding therefrom which contacts or nearly contacts the other roller when the roller containing the knife blade is rotated, a web to be severed being disposed between the two rollers. Also known to the art are rotary die cutting devices composed of a cutting roller and an anvil roller. Cutting elements known as cutting rules are mounted on the cutting roller for rotation therewith. The anvil roller is provided generally with a cover known as a blanket which fits around the surface of the anvil roller. The axes of rotation of the cutting roller and the anvil roller are parallel and displaced by an amount such that at their points of closest proximity the cutting rules penetrate the surface of the blanket.
Such devices of the nature with which the present invention is concerned have readily apparent difficulties in properly cutting and separating composite structures composed of sundry unrelated materials of varying degrees of resistance to cutting or shearing characteristics. In the case of cutting completely through a battery grid prepared by conventional operations, the separator-cutter device must effectively cut through metal that has been pasted as well as through at least two webbing materials such as paper and the like. This latter material in conjunction with the others often presents a difficult matter to properly and consistently sever in battery grid manufacture. Admittedly, it is important that a good, clean cut be made on a moving workpiece without interrupting the movement of the workpiece. This must be accomplished many times in a commercial setting.
Periodically, the knife blades or cutting edges must be replaced in order to maintain maximum use of the power loading factors on the cutting machine and to produce a clean shear edge on the workpiece. Longer life and ease of replacement of the cutting edges on the blades are desired goals if they produce a minimum of expense in returning the blade cutting edge to its original condition.
In a way of general background a conventional battery grid is made by a series of steps consisting of (1) expanding a metal strip, (2) flattening and sizing the expanded strip, (3) pasting and papering, (4) drying, (5) cutting and separating the pasted, paperbound strip to form grid structures and (6) enveloping the grid by folding a separator around and sealing the same.
The step of expanding in the process to form the expanded structure may be readily made by conventional processes, such as disclosed in U.S. Pat. No. 3,891,459. After expansion, pasting of the expanded structure is accomplished by moving it into a zone where an active material, generally a thick, lead-containing paste, is applied to the grid network. Various means may be used to apply the active material to the expanded structure. In order to deliver a uniform charge for distribution upon and into the open network of the grid without materially deforming the same, pasting machines are utilized and are generally of the so-called Lund or fixed orifice type or the Winkel or belt type. In the Lund type, a strip of battery paste is fed between a pair of rollers rotating to apply pressure to the grid, the paste being thereby forced into the grid structure. In the Winkel belt type, the grids are fed horizontally on a belt under a roller where the battery paste is applied. Pasting machines have also been developed that use ultrasonic energy to convert battery pastes from their normally nonflowable form to a flowable form. After the expanded structure is subjected to the direct and continuous charge of paste, the pasted grid is moved into a wiping or leveling zone where a doctor blade or the nip of a set of spaced apart rollers produce a uniform paste distribution. Generally, the pasting requires in conjunction therewith the laying down on paper on a continuous belt and passing it to the paste dispensing device and thereafter covering it with a second layer of paper followed by rolling. In this fashion the paste is compressed by mechanical forces into the interstices of the network, the leveling being such as to merely allow the grid structure itself to freely pass through the zone and undergo only minimum, if any, deformation. Thereafter, the pasted, paperbound grid is subjected to a drying operation to thereby affix the paste to the network. In a commercial operation, the production of grids is generally made from a large length of sheet material so that there are a multiplicity of grid structures thereon comprising expanded and unexpanded portions. After drying, the structures must be subjected to a separation or cutting operation to sectionalize and set free the individual grids for further processing. Since such structures are more or less in a delicate state, any slitting or cutting must be carefully done so as not to cause loss of paste from the pasted network. It will be appreciated that the battery grids are easily deformable and may lose their character if adequate means are not employed to handle them. Any undue treatment would cause disruption or loss of paste and, therefore, rejection of the grid structure.
Doughty, U.S. Pat. No. 2,609,945 discloses a battery plate feeding device that employs shearing discs to cut battery grid structures from a moving strip.
Huffman, et al., U.S. Pat. No. 3,310,438 discloses lead battery grid manufacture where expanded portions of a grid are pasted and thereafter subjected to blanking rolls whereby they are cut into finished grids.
Daniels, Jr., U.S. Pat. No. 3,867,200 discloses a method and apparatus for making battery grids in a continuous process including applying an active paste material to the grids, sandwiching the pasted grids between strips of paper and finally segmenting or cutting the pasted strips into individual battery plates.
Briefly, in accordance with this invention, an apparatus for cutting individual battery grids from a continuous sheet of pasted grid stock sandwiched between overlying and underlying webs comprising a first rotatably mounted cylinder having a cutting pattern including first cutter means lying transverse to the longitudinal axis of said first cylinder and cutting knives spaced from each other and from said first cutter means and lying parallel to the longitudinal axis of said first cylinder, and a second rotatably mounted cylinder spaced from said first cylinder and having second cutter means cooperating with said first cutter means to cut lengthwise of said sheet, said second cylinder having anvil members secured along the periphery thereof and disposed to come into substantial alignment during rotation adjacent said cutting knives and spaced therefrom to make direct contact therewith, the surface hardness of said cutting knives and said anvil members being different, said cutting knives and anvil members cooperating together to sever the sheet including the overlying and underlying webs.
The aforementioned features with the objects and advantages which become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.